Scientists study possible responses to climate e...( Palo Alto CAThe future of the Earth ...)

Palo Alto, CAThe future of the Earth could rest on potentially dangerous and unproven geoengineering technologies unless emissions of carbon dioxide can be greatly reduced, a new study has found.

The report (published September 1, by the Royal Society, the UK's national academy of science) found that unless future efforts to reduce greenhouse gas emissions are much more successful than they have been so far, additional action in the form of geoengineering will be necessary to cool the planet. However, the report identified major uncertainties regarding the effectiveness, costs, and environmental impacts of geoengineering technologies.

"Reducing our greenhouse gas emissions is more important than ever," said coauthor Ken Caldeira of the Carnegie Institution's Department of Global Ecology, "but even with our best efforts, the Earth is likely to continue warming throughout this century due to inertia in the climate system. Cutting emissions can reduce but cannot eliminate the risk of a climate emergency." Possible climate emergencies include rapid collapse of the Greenland ice sheet into the sea causing major sea level rise, a shift in rainfall patterns causing massive global crop failures, or melting Arctic permafrost causing catastrophic release of the powerful greenhouse gas methane.

Professor John Shepherd, who chaired the study said, "It is an unpalatable truth that unless we can succeed in greatly reducing CO2 emissions we are headed for a very uncomfortable and challenging climate future, and geoengineering will be the only option left to limit further temperature increases. Our research found that some geoengineering techniques could have serious unintended and detrimental effects on many people and ecosystemsyet we are still failing to take the only action that will prevent us from having to rely on them. Geoengineering and its consequences are the price we may have to pay for failure to act on climate change."

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